A comprehensive study of non-Lorentzian resonant lineshapes in nested ring resonators for quantum and photonic applications

Microring resonators are pivotal in photonic and quantum technologies. Enhancing their versatility for various applications often involves integrating additional elements to modify their resonant lineshapes. In this regard, Nested Ring Resonators (NRRs) offer a novel approach to generate a variety of lineshapes without the need for supplementary components. The coupled resonant architecture of NRRs can induce phenomena such as Electromagnetically Induced Absorption, Electromagnetically Induced Transparency, Fano resonance, and double Fano resonance. This study comprehensively analyzes the different resonant lineshapes achievable with NRRs, highlighting their broad applicability. We identify the specific conditions required for each resonant phenomenon and closely examine their characteristics. The theoretical insights from our research enable the autonomous design and realization of various resonance lineshapes within an NRR, eliminating the need for additional components while maintaining device compactness for a wide range of practical applications.